1. Discipline of Physics, The University of Newcastle, Callaghan, New South Wales 2308, Australia
2. Laboratory for Materials Simulations, Paul Scherrer Institut, 5232 Villigen, Switzerland
3. National Centre for Computational Design and Discovery of Novel Materials (MARVEL), Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
4. Discipline of Chemistry, The University of Newcastle, Callaghan, New South Wales 2308, Australia